Using spray guns to paint cars, houses, or other instrumentalities saves considerable time for the actual painting operation. However, when one job has been completed, a professional must clean his equipment in preparation for subsequent work.
Three forms of inefficiency arise at this juncture. First, since the painter is a skilled artisan, the chore associated with cleaning the equipment constitutes an inefficient usage of the skilled artisan's time. This loss of time can be considerable in industries such as the auto industry where color changes are frequent during the course of the day. This is true particularly when touch-ups or spray jobs entail spraying less than an entire vehicle. Second, the cleaning process while tedious, must be thorough. When using the gun for a subsequent job, the gun must be thoroughly cleaned to avoid contamination of the subsequent work. Third, cleaning has traditionally involved the use of solvents which are expensive and hazardous to the environment. Indeed, although barrels of solvent may sell for as little as $200.00 per barrel, the solvent cannot be reused and once contaminated must be transported to a toxic waste site where the disposal charge can exceed $250.00 per barrel.
The following patents reflect the state of the art of which applicant is aware and is tendered in response to applicant's acknowledged duty to disclose prior art. It is stipulated that the relevance of these patents is at best coincidental with the instant invention.
______________________________________ 3,255,972 Hultgren 4,405,088 Gray 3,714,967 Zupan, et al 4,471,911 Hengesbach 2,888,173 Wolcott ______________________________________
The patent to Hengesbach teaches the use of a spraying apparatus and method wherein the conventional spray gun has been modified to receive disposable containers to facilitate changing from one spray liquid to another. Thus, to facilitate the use of interchangeable containers, the spray gun lid is modified from normal mass produced spray gun lids to threadably fasten to the container.
The patent to Hultgren teaches the use of a collapsible container mounted within a rigid container and includes an aspirating tube extending into the collapsible container.
The patent to Grey teaches the use of an adapter for disposable cans which can be coupled to siphon type spray paint guns to achieve objectives similar to Hengesbach.
Zupan, et al is concerned with minimizing the amount of paint drip when using a siphon type spray gun assembly. To offset paint drip, a vent passageway is provided to alleviate the problem.
Finally, Wolcott teaches the use of a reusable pressurized container wherein an inner container is removeably mounted within the outer container for holding a quantity of material to be dispensed and a pressurized propellent.
First, it should be pointed out that known prior art teachings, while perhaps effective in alleviating certain problems, generate others because of the manner in which their solutions have been effectuated. For example, some appear objectionable because they require modification of existing paint equipment which can meet with considerable resistance on the part of the user. None of the teachings lend themselves to retrofitting on existing equipment without modification.
Structurally, users may find objectionable these known prior art teachings in that first, the rapid turnover from one fluid to the next would appeal primarily to professionals who have considerable experience in their field. Accordingly, a certain degree of reluctance exists in surrendering or modifying their familiar equipment some of which can be quite expensive, in exchange for an unknown quantity. Second, many of these modifications adversely affect the ergometric efficacy of the existing system particularly with respect to balance and weight.